The necessity to adapt the energy system due to limited energy resources and environmental damage, e.g. climate change, is today widely accepted. To understand, discuss, and manage the adaption a basic knowledge on the technologies used in the energy system is needed. The book tries to give a brief introduction in a way that is suitable for people without a higher scientific or technical education. It focuses on basic effects and general concepts, and tries to explain how things work without complex formulas; only basic physics and chemistry at a high school level is used. Crucial points are illustrated by examples. Additional information given includes sources of short movies in the internet that describe different technologies, often in action, and can be especially helpful for teaching. Further on, sources with a detailed scientific and technical treatment to go beyond a brief introduction are given. The book covers the essentials regarding energy, the different energy technologies, and finally how the different technologies are combined forming the energy system. The essentials introduce and explain the different energy forms, as there are mechanical, thermal, electrical, magnetical, chemical, and nuclear energy, the different types of processes of energy conversion, storage, and transport, and the exchange of energy as work and heat. Following the essentials is the description of the individual technologies for energy conversion, storage and transport. For each of them, the basics and the different technologies are discussed, starting from single step processes, as in materials, to multiple step processes, as in power plants. In the energy system, many of these technologies are connected to supply the desired energy to the user. Basic considerations on energy networks, a description of networks for thermal, electrical, chemical, and nuclear energy individually and their connections in the global energy system conclude the book.

Energy dominates our lives; anytime, everywhere, in many ways. Energy shows up in a variety of energy forms, for example when an object moves as kinetic energy, when lifted as gravitational energy, when compressed as deformation energy, when heated as thermal energy, and in the energy system as electric, magnetic, chemical, or nuclear energy. Energy can be converted between energy forms while it is overall conserved. How is it possible that a single term describes and relates such a variety of different things? Moreover, despite using the term "energy" almost anytime and everywhere, there is today no satisfactory explanation of what energy is; definitions range from "the ability to do work" to being "a number". Understanding the basics of energy takes the reader on a discovery of what energy is. It is based on the common concept that nature can be understood looking at the motion and interaction of objects, like particles, and applies this concept for the first time systematically from simple to complex situations. This way, the basics of energy can be understood, like the origins of the different energy forms, how energy is converted between them, and why energy is overall conserved. The book includes many examples and the historic background how the concept of energy evolved.